Adjustable stabilizer and fin



Aug. 25, 1931. w. K. EBEL ET AL ADZIUSTABLE STABILIZER AND FIN Filed July 19, 1928 5 Sheets-Sheet 1 M5 Mam n mi m aw VKM NT 1 a. W muvr wa Aug. 25, 1931. v w. K. EBEL ET-AL 1,820,271.

ADJUSTABLE STABILIZER AND FIN Filed July 19, 1928 3 Sheets-Sheet 3 INVENTORS WL'Nc'am K. Ebel L e ss ter- 62 Mz'lburn.

ATTORNEY5 Patented Aug. 25 1931.

UNITED STATES PATENT OFFICE:

winnnm gr. mama, or amma,

am) inssrrna c. MILBUBN, or-

omo, Assmuons are run cam L. Imam commmr, or CLEVELAND, OHIO, a

oonrona'non or one I amusraam 1 Application filed m 19,

This invention relatesto an airplane, being more particularly directed to the stabilizer and fin construction of the empennage or tail assembly thereof. e v

The tail assembly of airplanes includes a vertical fin for the purpose of steadying the rear end of the fuselage in straight flight and preventing too rapid side movement thereof when the rudder is manipulated, and s nce in planes using. a single engi e or multiple engines itis necessary to compensate for engine tor ue, .it'has heretofore been customary to a just the vertical fin or fins prior to flight. In addition to the vertical fin or fins, the'tail assemblies of airplanes are also provided with horizontal stabilizers servin the urpose of a steadying member and'ba ancmg the lane which 'might 'be tailor nose heavy. Xlthough these stabilizers, in many types of lanes, are fixed, bein set at zero angle an prov1ded w-'th a don le-cambered surface having no lift, it isobvious that adjustment of the stabilizer is desirable since, if the plane is tail'heavy, the angle of incidence of-the stabilizer may be set to secure a positive lift durin flight, or, if the plane is nose heavy, it may set at a negative angle so the tail willbe held down during flight.

It is often the case that because 0 varying load or other conditions it is desirable to change or adjust the angle of incidence of the stabilizer during flight, and because of stabilizers of certain types of planes have been adjustably' constructed. Heretofore, these adjustable Stabilizers have been arranged so that adjustment is secured by raising or. lowering theleadin edge of the stabilizers, the trailing edge t ereof being hinged to the. tail assembly. In adjusting this type of stabilizer considerable effort of operation is required because of the loads imposed upon the stabilizer such desirability the i during flight, for whichreasonthisform of construction has not ,proven' entirely satisfactory.

. such an adjustable stabilizer construction reauires the forward truss system to move or cat up and down as the leading edge of the stabilizer 1s or lowered and sincein.

rigid,

Another disadvantage lies in the fact that s'rammzan am) rm 1928. Serial No; 293,937.

large airplanes having two or more fins and ru ders the finsareusually attached to the movable stabilizer, a weak structure results 'which is subject both 'to play and fluttering in its moving parts. In attempting to overcome suchdisadvantages and secure the required strength rigid and cumbersome struc-. tures have been designed which create added resistance and excessive wei ht.

Therefore, the principal 0 j ect of the present invention is to rovide a construction for the stabilizer and of anairplane tail assembly wherein either or both the stabilizer 'or fin has the" majorpart thereof fixed with respect to the tail assembly and supported by a fixed truss system, but at the same time t e fin or stabilizer may be readily and indeadjusted during flight so as to pro -pendently vide various lift reactions for the former and adjustments of the latter to compensate for en e torque or other conditions.

. other object is to provide a fin and stabilizer construction for an airplane wherein the eflective camber'of these membersmay be adjusted during fli ht from the cockpit of the plane by sim 1i ed mechanism requiring a minimum of e ort.

Another object is to rovide a strong and yet simple and lig t, tail assembl construction for an airplane which inclu es an )adjustable fin and an adjustable stabilizer. 1

Additional objects and advantages will become apparent as the description of a preferred embodiment of the invention proceeds.

In carrying out the objects of thejnvem tion, it is contemplated to tical fin and'horizontal stabilizer of an airplane tail assembly of two portions; the rear portion of each member, forming the major part thereof and being fixed relative tothetail assembly,

while the forward portion forms substantially only the leadin' edge ,construct the ver-- part thereof and is hingedly co'nnecte to the other portion to move through a small angular displacement.

.An embodiment of, the invention is illustrated in the accompanying drawings wherein:

Fig. 1 is a fragmentar tail assembly of an airp ane fuselage;

side elevation 6f the i Fig. 2 is a section taken approximately on line 22 of Fig. 3, the dotted line portions of said figure illustrating diagrammatically the angular displacement of the elevator and of the leading edge portion of the stabilizer;

Fig. 3 is a plan'view showing the tail assembly of the plane;

. Fig. 4 is a section taken approximately on line 4-4 of Fig. 1, the dotted line portions of said figure illustrating diagrammatically the angular displacement of the rudder and the leading edge portion of the fin;

Fig. 5 is a side elevation of the airplane fuselage, the outlines of the fuselage being indicated by dot and dash lines, and the tail assembly thereof together with its operating mechanism being indicated in full lines;

Fig. 6 is an enlarged elevational view of the chain and sprocket mechanism which is installed in duplicate in the airplane cockpits for operating the adjustable leading edge portion of the stabilizer and fin; and

Fig. 7 is a rear elevation ofthe tail surfaces of the plane. I

The fuselage 10 of the plane may be of any desired construction and provided at its forward portion with one or more cockpits 11. The tail assembly of the plane includes the forwardly of the rudder, which fin has a fixed portion 13 and a movable leading edge portion 14 pivotally connected adjacent to usual rudder 12 and the vertical fin arranged its rear edge to the forward edge of the fixed portion. The tail assembly also includes the elevators 15, forwardly of which is the horizontal stabilizer comprising a fixed portion 16 and a movable leading edge portion 17. It should be noted that the fixed portion of both the vertical fin and stabilizer constitutes the major part of the respective members, while the movable portion of each constitutes, in effect, merely the leading edge portion, and it is because of this fact that the effort of operation in the adjustment of the movable portion of these members is reduced to a minimum and the strength of the tail assembly is not weakened. The movable portion of the stabilizer is pivotally mounted adjacent its rear edge upon a horizontally extending pivot 18, while its forward edge is operatively connected with anoperating or adjusting screw 19 adapted to move such edge upwardly or downwardly as the case ma be. The forwai'd edge of the portion 16 o the stabilizer is concaved so that the convex or rounded rear edge of the movable portion 17 thereof may be free to move to its various positions of adjustment, a slight clearance being also provided between the fixed and 'movable portions of the stabilizer to insure fIGQClOlll Of such movement. It should be observed that when the movable and fixed portions of the stabilizer are arranged in the position indicated in Fig. 1 that the forward edge of the stabilizer unit including these portions is, in efiect, merely a cambered surface and that no positive lift or depressing action of the stabilizer will take place.

j The operating or adjusting "screw 19 is rotatably mounted in bearings 20 secured to the side of the fuselage and is connected at its upper end to the forward edge of the movable portion of the stabilizer by a link 21. Interposed between the two lower bearings 20 is a hub member 22 having internal threads en-' gaging with the external threads upon the screw 19 and being provided exteriorly with a sprocket wheel 23 rigidly secured thereto and adapted to be turned by means of an operating chain, not numbered, which is connected to operating cables 24 and 25. It is thus apparent that when the cables 24 and 25, and, in turn, the operating chain, are moved in opposite directions, that the sprocket 23 and the hub 22 will be correspondingly rotated, thereby causing the shaft 19 to move upwardly or downwardly in its bearings, as the case may be, and, in turn, raising or depressing the leading edge of the movable portion 17 of the stabilizer.

The leading edge of the fixed portion 13 of the vertical fin is concaved inthe same manner as the leading edge of the fixed portion 16 of the stabilizer, while the rear edge of the movable portion 14 of the fin is convexed similarly to the corresponding edge of the ortion 17 of the stabilizer, the objects and a vantages of this arrangement having been fully set forth with respect to the stabilmen The movable portion 14 of the fin is operated by means of a screw shaft 26 rotatably carried in bearings 27 and 28 and connected by a linkage 29 to a bracket 30 carried by the lower end of such portion of the fin. An internally threaded hub 31 is arranged on the shaft between the bearings 27' and 28, which hub carries a sprocket wheel 32 engaged by a chain 33. This chain is connected at its opposite ends to the ope'ratingcables 34 and 35 in the same manner as the chain which encircles the sprocket 23 is connected to the cables 24 and 25. Since the manner inwhich all of the cables, namely, 24, 25, 34 and 35 are connected to the operating mechanism is the same, it will only be necessary to describe the connection between such operating mechanism and the cables 34 and 35, it being under- 34-and 35. It is thus apparent that when '2 the sproc ets derstood that in eitherof the cranks 38 and 39 is rotated in the desired direction, that the chains 40 and 41 will move around the sprockets 36 and 37 and, in turn, will move the cables 34 and 35, thus transmittilw the movement through the chain 33 to the sprocket 32 and causing adjustment of the vertical fin to be effected. However, inorder to limit the movement of the cables and, in turn, the adjustment of the fin, stops 44 and 45 are rigidly connected to the cables 34 and 35 by soldering or otherwise, and these stops are adapted to contact with the guides or floor leads 46 carried by and through which the cables pass. As already pointed out, the cables 24 and which are operatively connected to the' adjusting or operating. screw 19 for the horizontal stabilizer, are o eratively connected in the same manner b c ains 47 and 48 which encircle 49' and 50 likewise arranged adjacent to each the case of a single cockpit only one operating sprocket would be required and that the connection would. be

2 changed accordingly.

The construction just described provides for easy. adjustment of the fin and stabilizer from both of the oockpits and, therefore", en-

ables the pilot to make such adjustments as- 80 may become necessary during flight. The operatlng mechanisms for adjusting the rudder andelevato'rs have not been shown since the same may takethe form of any preferred construction, while the struts and wires used to rigidly brace the fixed portion 16 of the stabilizer are indicated at -51, 52 and 53, re

spectively. In Figs. 3 and 7 extra fins '54 and extra rudders 55 have been indicated,

such extra members being used in the case of multi-engine planes.

-Al hough a preferred embodiinent of the inventlon has been illustrated and described,

it should be understood that the invention 1s not to be limited thereto but may take such modifications and variations within the sec e of the following claims and that the speci 6 operating mechanism for the fin and stabilizer may take various forms, the one shown being simpl for pur oses of illustration. I IaVing-t us de'scri (1 our invention, we

claim:

1. An airplane construction comprising in ,the-tail assembly thereof a verticalyfin, said fin being formedmf two parts hingedly'connected together, the rearwardof said parts being fixed with respect to the tail assembly;

' and the forward of said parts being movable thereto.

2. -An airplane construction comprising in the'tail assembly thereof a vertical fi'n, said fin being. formed of two parts, the rearward -one of which includes su 'jor portion of the fin and is fixe with respectto' the tail assembly, while the forward one of which includessubstantially the leadthe fuselage the forward of said parts being movable cockpit. It should be unspect to ably mounte stantiall the .ma-

ing edge portion of the fin and is adjustably mounted with respect to the tail-assembly and to the other part of the fin.

- 3. An airplane construction comprising in the tail assembly thereof a horizontal stabilizer, said stabilizer being formed of a plurality of parts, one of which is fixed in-relation tosaid assembly and another of which is movable in respect to said fixed parts; the

forward edge'portion of said fixed part and the rear edge portion of a forward part being nested together in faired'relation.

4. An airplane construction comprising in the tail assembly thereof a horizontal stabilizer, said stabilizer being formed of two parts hingedly connected together in faired relation, the rearward of said parts being fixed with respect to the tail assembly and with respect thereto.

5. -An airplane construction comprising in the tail assembly thereof a horizontal stabilizer, said stabilizer being. formed of two. parts, the rearward one of which includes substantially the majorportion of the stabilizer and is ,fixed with respect to the tail as-: sembly, while eludes substantially the leading edge portion of the stabilizer and is adjustable with respect to said major portion, the rear edge portion of said leading edge portion nested in the forward one of which infaired relation with the forward edge portion of said major portion.

6. An airplane construction comprising in] ber' ly the leading edge portion of its respective member and is hi'ngedly mountedto'move through the other part and the tail assembly. 7. An airplane construction comprising a tailass'embly including avertical' fin, said fin being formed of'two one of which includes su stantially the'm'a; jor portion of the fin and is fixed with respectto the tail assembly, while the forward one of which includes substantial? onl the leading edge ortion of'the fin an is-adj d with respect to .the. tail, assembly and to the other part of the fin, and means associated and adapted to be operated from thecockpit. of the. plane for effecting adjustment-thereof."

8. tail assembly including'f la; horizontal sta ian angular displacement with re 1 arts, the rearward ust- 12 0 with said forward part of the fin An airplane construtioncomprisin a l-i'zer, said stabilizer bein f onned.of' two substantially sembly, while the forward one of which ineludes substantially only the leading edge portion of the stabilizer and is adjustable with respect to the tail assembly and the other part, and means adapted to operation from the cockpit for changing the streamlining relation between said parts to a cambered relation therebetween.

9. An airplane construction comprisinga tail assembly including, in combination, a vertical fin and a horizontal stabilizer, said fin and said stabilizer each being formed of two parts, the rearward of which constitutes the major portion of its respective member and isfixed relative to the tail assemblyand the forward part of which forms substan tially only the leading edge portion of its respective .member and is hingedly mounted to move through an angular displacement with respect to the other part and to the tail assembly, and independent means associated with the forward part of both the fin and the stabilizer and adapted to be operated from the cockpit of the plane for effecting adjustment thereof.

10. An airplane comprising a tail assembly including a vertical fin, said fin being formed of two parts, the rearward of which -is fixed with respect to the tail assembly and the forward of which is adjustable with respect thereto, an operating member associated with said forward adjustable part of the fin, actuating means arranged adjacent to the cockpit of the plane, and an operative connection between said operating member and said actuating means whereby said adjustable part of the fin may be moved through an angular displacement.

11. An airplane comprising a tail assembly including a horizontal stabilizer, said stabilizer being formed of two parts arranged in paired relation to each other the rearward of which is fixed with respect to the tail assembly and the forward of which is angularly movable with respect to said fixed part thereto, an operating member associated with said forward part of the stabilizer, actuatin means arranged adjacent to the cockpit of the plane, and an operative connectionbetween said operating member and said actuating means whereby said movable part of said stabilizer can be angularly displaced in relation to said fixed part thereby creating variable stabilization.

12. An airplane comprising a tail assembly including, in combination, a .vertical fin and a horizontal stabilizer each of said members having a' rearward fixed part forming the major ortion of its respective member and a part forming substantially only the Jeading edge portion of its respective member, an operatim member associated with the forward ad ustable part of each of said first named .members, independent actuating orward adjustable arranged adjacent to the cockpit of the plane,

and an operative connection between each of said operating members and its respective actuating means whereby the fin and stabilizer may be adjusted.

13. An airplane construction combining in the tail section thereof a vertical fin comprising two .main parts, one of said parts fixed in relation to said section and the other of said parts hingedly movable in front angular relation to said fixed part, and-a rudder hingedly movable in rear angular relation to the fixed part of said fin.

14. An airplane construction combining in the tail section thereof a vertical fin comprising two main parts, one of said parts fixed in relation to said section and the other of said parts hingedly movable in front angular relation to said fixed part, a rudder hingedly movable in rear angular relation the other of said parts hingedly movable in 4 front angular relations to said fixed part,

, said parts faired in nested endwise relation to each other, and an elevator hlngedly movable in rear angular relation to the fixed part of said stabilizer.

16. An airplane construction combining in the tail section. thereof a horizontal'stabilizer comprising a major and a m nor main. part, the major of said parts fixed m'relation to said section and the minor of said parts hingedly movable in front angular relation to said fixed part, said parts faired in nested endwise relation to each other, an elevator hingedly movable in rear angular relation to the major part ofsaid stabilizer, and means in the cockpit cooperating with means connected-inoperative relation to said movable part whereby said angula'r'relatlon may be controlled therefrom.

17. An airplane construction comprising in the tail assembly thereof a vertical fin, said fin-being formed of two parts, the rearward of said parts being fixe' said assembly and the forward of said parts hinged in relation to said rearward part and said assembly; the forward edge portion of said fixed part and the rearward edge portion of said hinged part being nested together in faired relation.

18. An aircraft construction comprising in.

the tail assembly thereof a vertical fin, said fin being formed ofthree parts hingedly connected together in tandem relation; the intermediate of said parts being fixed in relain relation to.

tion to both of said hinged parts and the contiguous edge portions of said xed part and of said forward part nested each with the other. I

19. An airplane construction comprislng in the tail assembly thereof a horizontal stabilizer, said stabilizer being formed of two parts, the rearward of said parts being fixed in relation to sa1d assembly and the forward of said parts hinged in relation to said rearward part and said assembly; the forward edge portion of said fixed part and the rear edge portion of said hinged part being nested to ether in faired relation.

, minor portion is adjusted in tandem with 20. 11 an aircraft, a horizontal stabilizer comprising a minor forward portion, and a major rear portion fixed with respect to said aircraft; said minor portion hinged in nested relation to said major portion; said minor portion and said'major portion adapted by their cooperative contours to form a streamlined stabilizer when adjusted in tandem relation and to form a cambered stabilizerwhen adjusted in angular relation; means for adjusting said portions to either of said relations.

21. In an aircraft, a horizontal stabilizer comprising a minor forward portion, and a major rear portion fixed with respect to said aircraft; said minor portion hinged in nested relation to said major portion, said portions being in streamlined relation when said said major portion and in cambered relation when said mlnor port1on 1s angularly ad usted to said fixed portion; and means adapted to operation from the cockpit for adjusting said movable portion from a streamlining relation to a cambering relation with said fixed ortion.

22. n an aircraft stabilizing system, a

stablizing member in which a minor forward portion is hinged in endwise nested faired re-' lation to a major portion, said major portion fixed in relation to a supporting structure;

a dual remote control mechanism for said hmged part; said mechamsm comprislng a sprocket wheel and an associated screw shaft adapted to adjust said minor part in angular relation to said ma or part, a sprocket chain adapted to rotate said wheel, a second and a third sprocket wheel spaced apart in tandem relation and operatively attached to said structure; said second and third sprocket wheels coactively rotatable by a" second' sprocket chain, the ends of said first chain operatively connected with said second chain intermediate said second and third sprockets, and a crank for each of said second and third sprocketsfor manual operation of said In testimony whereof, we hereunto aflix our signatures. I

WILLIAM K. EBEL. LESSITER v(3. MILBURN. 

